Longitudinal and thickness measurement of the normal distal and intravesical ureter in human fetuses.

Abstract

We define reference data concerning the development of the ureterovesical junction in fetuses and newborns by measuring the diameters of the distal mesenchymal and muscular ureteral walls as well as intravesical ureteral length. A total of 90 normal fetal and newborn ureters were investigated. Our histological studies were based on "plastinated" sections of whole pelves which allow study of the sectional anatomy of the distal and intravesical ureter. The development of the mesenchymal and smooth muscle growth of the distal and intravesical ureter was examined. The ureteral measurements were correlated with age of gestation. The length of the intravesical ureter and mesenchymal as well as smooth muscle walls increased in a linear mode. Significant correlations (p <0.0001) were found between gestational age and the growth of the mesenchymal as well as smooth muscle walls in the distal intravesical ureter as well as the length of the intravesical ureter. Significant positive linear relationships exist between gestational week, and distal and intravesical ureteral wall thickness of the mesenchymal and smooth muscle growth to the length of the intravesical ureter in fetuses and newborns. The ratio of the intravesical ureteral length-to-ureteral diameter is obviously lower than assumed previously. Data from this study can be used for a more accurate assessment of cases with abnormal lower urinary tract development.